Best Free Browser DevTools Tools in 2026

Dia is a specialized browser engineered to optimize professional workflows by intelligently organizing information and proactively suggesting relevant content. It acts as a central hub, integrating with various work tools like GSuite, Slack, Notion, and GitHub to provide a unified view of tasks and information. Dia aims to reduce context switching and information overload, allowing users to concentrate on deep work. The browser features include a "Morning Brief" for daily overviews, "Proactive Suggestions" that surface next steps, and an AI-powered search that answers questions by analyzing context across connected applications. It also offers features for better meeting preparation, distinct work and personal profiles, and advanced tab management. Dia prioritizes user privacy with local data storage, end-to-end encryption for synced data, and strict controls over data sharing for product improvement.

SigmaOS is a fresh take on the web browser, designed to enhance productivity and reduce digital clutter. It introduces a unique workspace-based organization system, treating tabs like tasks that can be marked as done or locked. The browser features vertical tabs for better overview, split-screen multitasking, and an integrated ad blocker for a cleaner browsing experience. Beyond organization, SigmaOS incorporates advanced AI capabilities through its companion, Airis. Airis can understand the context of the website you're on to answer questions, explain paragraphs, and even conduct internet searches to provide a starting point for research. It also offers a 'Simplify' feature to distill web pages into interactive summaries, aiming to create a more peaceful and focused internet environment. SigmaOS is ideal for users seeking a more structured, efficient, and intelligent way to interact with the web.

Comet is Perplexity's AI-powered web browser. It builds Perplexity's answer engine directly into the browser, letting you ask questions about any page, summarize articles, and use an AI assistant that can take actions across your tabs. It is positioned as an agentic browser that completes tasks, not just one that displays pages.

Requestly is an open-source, lightweight API client and web proxy designed for modern developers to build, test, and debug APIs efficiently. It offers both a browser extension for instant, in-browser functionality and a more powerful desktop application for Mac (with other platforms implied) to handle web, mobile, and desktop app API interactions. Beyond just an API client, Requestly functions as a robust HTTP interceptor and web debugger. It allows developers to intercept and modify network requests, headers, and API responses in real-time. This includes injecting custom scripts (JavaScript/CSS), mocking API responses to build frontends without a backend, simulating edge cases, and redirecting requests. It aims to streamline development workflows by providing a comprehensive tool for API development, testing, and debugging, reducing the need to juggle multiple tools. Requestly also emphasizes collaboration and enterprise-readiness with features like team workspaces, Git synchronization for API collections, role-based access control, and robust security measures including SOC-II compliance, SSO, and data encryption. It positions itself as a powerful, open-source alternative to more 'bloated' closed-source solutions, offering a fast, flexible, and secure environment for API development and debugging.

Agent Browser enables AI agents to navigate, click, type, and interact with real web browsers using ASCII wireframes, a text-based representation where interactive elements are numbered for efficient token usage. Instead of processing heavy screenshots, AI models receive structured wireframes that maintain semantic clarity while minimizing cost and latency. Built on Playwright, it integrates with MCP clients (Claude Desktop, Cursor), the Vercel AI SDK, and offers an interactive CLI for manual testing.

WizzyPoke is a Chrome extension that allows users to send "nudges" to their friends, reminiscent of the classic MSN Messenger feature. These nudges shake the recipient's screen, aiming to get their attention when messages might go unnoticed. It's designed for personal use to add a fun and immediate way to communicate. The tool works across popular web applications like WhatsApp Web, YouTube, and Netflix. It prioritizes privacy by using unique 6-digit codes for pairing friends instead of phone numbers. WizzyPoke is ideal for individuals looking for a playful and effective way to get a friend's attention online, especially when text messages aren't cutting through the noise. Key benefits include instant delivery of nudges, easy friend pairing, and the ability to make communication more engaging. It offers a free tier for basic use and a one-time purchase for unlimited nudges and broader web app support.

ADB Wrench is a browser-based tool designed to simplify Android debugging. It allows developers to connect to Android devices directly from their web browser, eliminating the need for local ADB installations or complex command-line interfaces. This makes it easier to inspect device state, install/uninstall apps, pull/push files, and execute shell commands. The tool is ideal for Android developers, QA engineers, and anyone who needs to interact with Android devices for development, testing, or troubleshooting. Its browser-based nature enhances accessibility and collaboration, as it can be used from any machine with a web browser without environment setup. Key benefits include increased productivity, reduced setup time, and a more streamlined debugging workflow.

StealthHound is a Chrome extension designed to protect user privacy by detecting and blocking advanced tracking techniques like browser fingerprinting. Unlike traditional ad blockers or VPNs, it specifically targets invisible tracking methods that websites use to identify devices even without cookies or logins. It provides real-time risk signals, live alerts for hidden tracking attempts, and automatically blocks invasive techniques. This tool is ideal for anyone who wants greater clarity and control over their online privacy, from everyday users to developers and privacy-conscious professionals. It operates locally within the browser, ensuring no browsing history collection, user tracking, or data selling, making it a privacy-first solution. StealthHound aims to make hidden tracking visible and controllable, empowering users to understand and prevent how websites behave.

KanjiLens is a browser extension designed to help Japanese learners master kanji through immersion. It allows users to read their favorite manga and novels online, providing instant kanji lookup by hovering over any character to see its reading and meaning. This eliminates the need to break reading flow for dictionary lookups. The tool also features one-click image translation, utilizing OCR technology to seamlessly translate text within manga panels and other images, making raw Japanese content more accessible. An integrated Spaced Repetition System (SRS) allows users to save new words to personalized flashcard decks, aiding long-term memory retention. Additional features include right-click scanning, custom mnemonics, and customizable settings, making it ideal for anyone looking to learn Japanese by engaging with native content.

Edge Light is a browser extension that applies professional virtual ring light effects to video calls without requiring physical lighting hardware. It creates a soft, adjustable glow on the browser tab to keep faces well-lit during video conferences on Zoom, Google Meet, Microsoft Teams, and other web-based platforms. All lighting effects are processed locally in the browser with no data uploads, ensuring complete privacy. Available for Chrome, Edge, Brave, and Firefox.

Screen Ruler is a powerful Chrome extension designed for web developers and designers to inspect elements, measure distances, extract assets, and validate designs directly within their browser. It provides a comprehensive suite of tools for analyzing web pages, from basic element inspection and distance measurement to advanced CSS analysis, accessibility checks, and SEO issue detection. The tool helps streamline the web development and design workflow by consolidating multiple functionalities into one extension, eliminating the need for several standalone tools. It's ideal for ensuring design accuracy, identifying potential issues, and efficiently extracting necessary assets during the development process. The Pro version further enhances capabilities with features like asset extraction, responsive mode testing, technology detection, and advanced CSS visualization tools.

MiroMiro is a Chrome extension designed for designers and developers to quickly extract and copy UI elements and design system details from live websites. It allows users to inspect, edit, and copy CSS and Tailwind properties, export production-ready HTML, and download various assets like images, SVGs, and Lottie animations with a single click. This tool aims to streamline the workflow by eliminating the need for manual inspection through DevTools or describing UI elements to AI. The extension is particularly useful for frontend developers, UI/UX designers, and no-code builders who need to quickly replicate designs, extract brand assets, or build UIs based on existing websites. It integrates with AI tools like Cursor, Claude, v0, and Lovable by providing them with exact code and design tokens, enhancing the accuracy of AI-generated UI. MiroMiro also includes features for checking WCAG contrast on the page and building a personal swipe file of bookmarked components and assets, all while ensuring user privacy by processing extractions locally.

Omi A11Y is a free Chrome extension designed to help developers and designers quickly identify and fix web accessibility issues. It scans any webpage directly in the browser for violations of WCAG 2.1 A and AA standards, providing instant feedback without requiring any sign-ups or changes to build pipelines. The tool aims to integrate accessibility into every developer's workflow by offering clear, actionable guidance on complex standards. The extension performs 25 automated checks, covering common issues from missing alt text and keyboard traps to color contrast problems. It allows users to jump directly to failing elements on the page with a single click, eliminating the need to manually search through source code. Omi A11Y provides plain-language explanations of why an issue matters and how to resolve it, making it accessible for both experienced accessibility auditors and those new to the field. It also includes a Focus Order Visualiser and the ability to export reports.

HighlightGPT is a Chrome extension that lets you highlight text inside ChatGPT and interact with it in a side panel. Select any text in a ChatGPT conversation, and the extension opens a panel where you can ask follow-up questions, get explanations, translate content, or save responses to ChatGPT's memory, all using ChatGPT's native responses with zero extra token cost. The side panel keeps your main conversation uninterrupted. Lifetime pricing: free or $8 one-time for Pro.

Checkbot is a powerful Chrome extension designed to audit websites for over 50 best practices related to SEO, web speed, and security. It can crawl hundreds of pages in minutes, identifying issues such as broken links, duplicate content, invalid HTML, insecure forms, redirect chains, and more. The tool provides immediate feedback, allowing users to catch critical problems during development before they impact users or search rankings. This tool is ideal for web developers, SEO specialists, product managers, and anyone involved in website optimization. It helps save time on manual testing by effortlessly and reliably checking numerous pages, uncovering hard-to-spot problems that might otherwise be missed. Checkbot also offers in-app guidance to explain identified issues, why they are important, and how to fix them, making it accessible even for those new to website optimization. It supports testing of unlimited sites, including local development and password-protected pages, ensuring continuous website health.